# Cavallo's Multiplier for in situ Generation of High Voltage

## TL;DR

This paper explores Cavallo's multiplier as a simple, effective method for generating very high voltages in cryogenic environments, with analysis, experimental validation, and design considerations for large-scale applications.

## Contribution

It provides a quantitative analysis of Cavallo's multiplier using capacitance measurements, demonstrates a working prototype, and discusses optimization for cryogenic high-voltage generation.

## Key findings

- Measured voltages closely match predictions based on capacitance data.
- The device is suitable for high-voltage generation with minimal load current in cryogenic conditions.
- Design insights enable optimization for large-scale cryogenic experiments.

## Abstract

A classic electrostatic induction machine, Cavallo's multiplier, is suggested for in situ production of very high voltage in cryogenic environments. The device is suitable for generating a large electrostatic field under conditions of very small load current. Operation of the Cavallo multiplier is analyzed, with quantitative description in terms of mutual capacitances between electrodes in the system. A demonstration apparatus was constructed, and measured voltages are compared to predictions based on measured capacitances in the system. The simplicity of the Cavallo multiplier makes it amenable to electrostatic analysis using finite element software, and electrode shapes can be optimized to take advantage of a high dielectric strength medium such as liquid helium. A design study is presented for a Cavallo multiplier in a large-scale, cryogenic experiment to measure the neutron electric dipole moment.